1. Field of the Invention
The present invention relates to an image data outputting apparatus and an image data outputting method, and more particularly to an image data outputting apparatus and an image data outputting method that output copy forgery preventing image data for preventing copy-based forgery to an image forming apparatus for forming images, based on forgery prevention target image data to be protected from copy-based forgery.
2. Description of the Prior Art
A virtual shop for selling commodities on a computer network such as the Internet or intranet has the convenience that the user can purchase various commodities by accessing the shop from a terminal. The contents dealt by the virtual shops are rapidly increasing to tours, music, books, insurance, and the like. Through a virtual shop, various commodities can be sold without displaying the commodities in an actual shop. Consequently, in many convenience stores, multimedia terminals are installed.
In recent years, by providing or connecting a color printer in/to the multimedia terminal, real-time on-demand output service such as sales of a picture of a star is becoming available. Since the convenience of the virtual shop further increases by such real-time on-demand output service, expansion of the contents, for example, issuance of securities such as a gift certificate, various tickets such as airline ticket and show ticket, a certificate of residence, and the like is expected.
In spite of the fact that a picture of a star or the like can be copied by a color copier, under present circumstances, no measure of protecting the copyright and the rights to one's portrait is taken. There is also the possibility that a secret document such as a certificate of residence related to the privacy of an individual, securities and a ticket are forged or counterfeited by being copied. When a measure of preventing illegal copying is not taken, such a secret document cannot be directly outputted from a printer by operating, for example, the multimedia terminal installed in a convenience store.
Conventionally, to prevent illegal copying of a secret document, a special sheet called a copy forgery prevention sheet is used. The copy forgery prevention sheet is a sheet on which a special pattern of characters of warning or the like which is not easily seen by the eyes of a human but appears when the sheet is copied by a copier is printed in advance. When a document printed on the copy forgery prevention sheet is copied by a copier, letters of warning such as “copy prohibited” appear conspicuously on a copy. An illegal act of copying can be psychologically suppressed, and the original and a copy can be discriminated from each other by the characters of warning.
When such copy forgery prevention sheets are loaded in a printer installed in a convenience store or the like and document data read from a database by operating the multimedia terminal is printed on the copy forgery prevention sheet, a secret document such as certificate of residence, securities and a ticket can be directly outputted from the printer.
Since special printing has to be performed in advance, the copy forgery prevention sheet has a problem such its cost is higher than a sheet used by an ordinary copier or printer. In the case of changing a design of a background pattern, a logo, a symbol mark, or the like, printing on sheets has to be newly performed. Consequently, it is not easy to change something in the sheet.
As for an example of certificates such as certificate of residences issued by city offices, the city offices use copy forgery prevention sheets of kinds unique to the city offices, and also use different kinds of copy forgery prevention sheets, depending on the kinds of certificates. Therefore, users managing multimedia terminals must provide numerous kinds of copy forgery prevention sheets, locate copy forgery prevention sheets according to certificates, and exchange them with sheets placed on a tray to start printout, imposing heavy loads on the users. If the kinds of copy forgery prevention sheets are changed, post-change copy forgery prevention sheets must be distributed to users who install multimedia terminals. Moreover, the users must carefully manage copy forgery prevention sheets to prevent malicious use of them, and bear the management cost.
The applicant of the present invention proposes a recording medium outputting method that allows a recording medium to be printed without using copy forgery prevention sheets by performing printout after merging copy forgery preventing image data capable of preventing copy-based forgery according to forgery prevention target image data to be protected from copy-based forgery . U.S. application Ser. No. 09/853,576. According to the present invention, documents to be protected from copy-based forgery such as certificates issued by city offices can be outputted without using copy forgery prevention sheets.
However, two or more models such as monochrome printer and color printer may coexist in a convenience store or the like. Also, where printers are changed to a new model, it is difficult to replace all of a large number of printers at the same time, and there will occur a period during which new and old models coexist. On the other hand, where a recording medium printed by merging copy forgery preventing image data is to be outputted, although a copy forgery preventing image is buried as a latent image, it may be reproduced differently on the recording medium, depending on resolution and tone property, or printer characteristics specific to color printers and monochrome printers. As a result, the copy forgery preventing image, which should be latent, may be conspicuous depending on the model of a printer to which it is outputted, posing the problem of impairing the quality of a visible image.